Description

This command is used to define local material directions in anisotropic materials such as fiber composites.
The user defines the location and orientation of a "ply" in space. This ply is then wrapped around the component.

Note that models with more than one element in thickness direction require special consideration.
For such models the wrapping algorithm requires a mesh with elements that are larger
in-plane than in thickness direction.

The ply first needs to be projected onto the component.
This projection generates intermediate in-plane directions $\bar{\mathbf x}$ and $\bar{\mathbf y}$.

where $\hat{\mathbf z}$ is the local face surface normal direction. The local fiber direction
$\hat{\mathbf x}$ and the orthogonal direction $\hat{\mathbf y}$ can now be defined by rotating
the intermediate directions with the angle $\alpha$.